Sunscreen composition containing sol-gel microcapsules

ABSTRACT

The present invention generally relates to safe and stable sunscreen compositions comprising of at least one sunscreen active ingredient in the form of an inert sol-gel microcapsules encapsulating ultraviolet absorbing compounds in any acceptable cosmetic vehicle. The composition according to the present invention can comprise several ultraviolet absorbers that may be encapsulated in the same sol-gel microcapsule or in different capsules. The hydophobicity/hydrophilicity character of the sol-gel microcapsules can be controlled by selecting suitable sol-gel precursors and suitable reaction conditions and can be chosen to be compatible with the cosmetic vehicle to be used in the sunscreen composition, thus, the present invention facilitates an easy incorporation of the composite sol-gel encapsulated sunscreen in all types of cosmetic vehicles including oil free compositions, with no necessary steps of heating or high shear forces. The sunscreen compositions of the present invention can comprise any acceptable UVA and/or UVB absorbing compounds at any desired ratio to obtain a desired accumulative ultraviolet screening spectrum.

RELATED APPLICATIONS

The present application is a continuation-in-part of application Ser.No. 09/318,828 filed May 26, 1999, entitled “SUNSCREEN COMPOSITIONCONTAINING SOL-GEL MICROCAPSULES”, now U.S. Pat. No. 6,238,650.

FIELD OF THE INVENTION

The present invention generally relates to safe and stable sunscreencompositions. More specifically the present invention relates to asunscreen composition comprising at least one sunscreen activeingredient in the form of inert sol-gel microcapsules encapsulating UVBand/or UVA sunscreen compounds (ultraviolet absorbers), in anyacceptable cosmetic vehicle. The composition according to the presentinvention can comprise several ultraviolet absorbers that may beencapsulated in the same sol-gel microcapsule or in different capsules.The encapsulation of the ultraviolet absorbers makes the compositionsafer for use, since the encapsulating sol-gel material forms a barrierthat reduces or even prevents contact between the sunscreen compoundsand human tissue. Hence, various adverse effects that are associatedwith the use of sunscreens, such as photoallergy and phototoxicity areprevented. Furthermore, the encapsulation reduces or even prevents crossreactivity between different sunscreen compounds when more than one suchcompound is present in the composition, between the sunscreen compoundsand the packaging material and between the sunscreen compounds and anyother component present in the composition. The present inventionfacilitates an easy incorporation of the composite sol-gel encapsulatedsunscreen in all types of cosmetic vehicles including oil freecompositions, with no necessary steps of heating or high shear forces.

BACKGROUND OF THE INVENTION

Sunscreens compositions are chemical compositions, which are usuallyapplied topically to skin and hair in order to protect them from thedamaging effects of the sun's radiation, especially against ultraviolet(UV) radiation.

The damaging effects of sunlight exposure on skin and hair are welldocumented. These effects include increased incidence of skincarcinogenesis, pigmentation, anomalies and precancerous lesions such asactinic keratosis, melanoma and nonmelanoma skin cancers, as well asaccelerated skin aging and undesirable changes in hair quality. Inrecent years, a growing number of studies show that damage is caused notonly by the UVB irradiation (290-320 nm), but also by UVA irradiation(320-400 nm).

The use of UV absorbing chemicals for human application is regulated bythe health authorities. In the US and Australia sunscreens are regulatedas over-the-counter (OTC) drugs, consequently introduction of newsunscreen active ingredients requires heavy investment of time andmoney. Most of the UV absorbing agents allowed for use are UVBabsorbers. These include para amino benzoates, salicylates, cinnamates,anthranilate, camphors and miscellaneous chemicals. The number of UVAabsorbers is more limited, with benzophcnones (UVB and UVA absorber) anddibenzoylmethanes (UVA absorber) being the most widely used.

Recently new UV absorbers have entered the market. Examples of such UVabsorbers are: Octyltriazone, Drometrizole trisiloxane, andDimethico-diethyl-benzal-malonate.

Some of the sunscreen active ingredients have been found to causephotoallergy and photosensitization reactions, encouraging themanufacturers to avoid using them. For example, growing public awarenessto the photosensitization reactions of PABA and its derivatives hasencouraged the use of PABA free products (see S. Schauder and H. Ippen,European UV Sunfilters, Conference Proceedings, Paris November 17-181998, p. 14). The production of another sunscreen, 4-isopropyl dibenzoylmethane was ceased in 1993 due to the high number of photoallergyincidents reported for this active ingredient (Ibid). Moreover, some ofthe reported cases of adverse reactions to sunscreen active ingredientsrelate the adverse reactions to cross reactivity of several sunscreeningredients, as in the case of cross sensitization between differentcinnamate derivatives (Ibid). Moreover, several research groups havedemonstrated the photoinduced DNA damage and phototoxicity of severalsunscreen agents, including Padimate-O (Knowland et al, FEBS Letters,324, 309-313, 1993), Phenylbenzimidazole sulfonic acid (C. Stevenson andR. J. H. Davies, Chem. Res. Toxicol, 12, 38-45, 1999). Physicalsunscreens such as titanium dioxide are known to be photocatalystscapable of rupturing covalent bonds (U Stafford, K. A. Gray and P. V.Kamat, Heterogeneous Chem Rev. 3, 77-104, 1996), and have been shown toproduce reactive oxygen species under illumination (W. C. Dunlap et al,Int. J. Cosmetic. Sci. 20, 1-18, 1998).

With the growing demand for higher SPF values and for broad-spectrumprotection, manufacturers are forced to combine several activeingredients at increased concentrations (often the maximum permittedconcentrations), hence the problem of cross reactivity between sunscreenactive ingredients is becoming more severe. An example for crossreactivity effects is the photoinduced interaction between butylmethoxydibenzoylmethane (also known as4,4′-methoxy-t-butyldibenzoylmethane or BMDBM), an excellent UVAabsorber, with the most widely used UVB absorber octyl methoxycinnamate(R. M. Sayre et. al, 26^(th) Annual Meeting if the American Society forPhotobiology, Abstr. No. SPM-A7). This cross reactivity contributessignificantly to the photochemical instability of both the UVB and theUVA active ingredients. Another problem associated with BMDMB thatpresents a number of composition problems, is its tendency to react withactive methylene groups such as those present in formaldehyde releasingpreservatives at temperatures above 30° C., thus restricting the use ofsuch preservatives (W. Johncock, Sun Protection The Influencing Factorsin Creating Effective Products, March 1999 London, March 1999 andreferences therein).

Another problem, associated with the use of high sunscreen compoundsconcentrations, is the tendency of some of these ingredients tocrystallize at certain pH range, or if the amount of oil in thecomposition is not sufficient.

Yet, another problematic aspect in sunscreen products is the selectionof packaging material. Liquid UVB filters permeate into various plasticpackaging materials (polystyrene as one example), and consequently causedecomposition or coloration of the packaging materials. UV absorbingliquids are able to permeate polymers like polystyrene, low densitypolyethylene and polyethylene terphthalate. This can cause fracturing ofthe packaging material, unacceptable colouring of white packagingmaterial with time, and assay problems such as ensuring that the propercontent of active ingredients are maintained upon storage.

In the present invention it has been found that if the sunscreen activeingredients are introduced into the cosmetic vehicle in the form ofsol-gel encapsulated sunscreen, cross reactivity of sunscreen activeingredients, e.g. butyl methoxydibenzoylmethane and octylmethoxycinnamate, can be reduced or even prevented. The separateencapsulation of sunscreen active ingredients in the sol-gel derivedcapsules creates a barrier that prevents cross interactions betweenthese active ingredients. Furthermore, the encapsulation of UV absorbingliquids in sol-gel derived capsules reduces the contact between theseliquids and the packaging material. Consequently, the problem of adversereactions caused following permeation of the sunscreen activeingredients into the packaging material is diminished. Furthermore, theuse of sol-gel encapsulated sunscreens facilitate the incorporation, inthe same composition, of several components that are incompatible whensimply dissolved in the composition, for example 2-phenylbenzimidizole-5-sulfonic acid with α or β hydroxy acids. The presentinvention also allows easy incorporation of solid sunscreen activeingredient or active ingredients that tend to precipitate in variouscompositions, since even in a situation that solid is formed, thecrystals are confined within the sol-gel capsules, hence, a pleasant nongritty feel and efficient spreading are maintained. Yet anotheradvantage of the present invention is the ability to control thehydrophilicity/hydrophobicity character by choosing a suitable sol-gelencapsulating material, thus the encapsulated sunscreen can beconveniently introduced into the composition.

It is an object of the present invention to provide safer sunscreencompositions by reducing or even preventing the contact of the lightabsorbing molecules (sunscreen compounds), or their possiblelight-induced degradation products, with human tissue.

It is another object of this invention to provide a stable and safersunscreen composition by reducing or even preventing cross reactivitybetween various ingredients present in the same composition.

It is a further object of this invention to reduce or even to preventthe deleterious permeation of sunscreen active ingredient into plasticpackaging materials which may result in fracturing of the packagingmaterial, unacceptable colouring of white packaging material with time,and assay problems.

It is a further object of this invention to provide the formulator withan easy-to-use sunscreen active ingredients, which can be incorporatedeasily, without applying heat or high shear forces, in any cosmeticallyaccepted vehicle.

Yet it is another object of the present invention to provide an easyincorporation of solid sunscreen active ingredient or of activeingredients that tend to precipitate, in various compositions, tothereby maintain a pleasant non gritty feel and efficient spreading.

The compositions revealed by this invention are of general nature, andthe method according to which they are prepared is applicable to anysunscreen compounds currently used, as well as to sunscreen compoundsthat will be introduced in the future. It is also applicable for othercompounds that are regularly used in cosmetic compositions. Furthermore,because of the easy incorporation of the sunscreen active ingredientsand the ability to control their hydrophilicity/hydrophobicity characterand the capsules size, the cosmetic vehicle to be used with thesunscreen active ingredients is not limited to any group and can be anycosmetically acceptable vehicle.

In the context of the present invention the term “sunscreen compound”refers to an ultraviolet (UVA and/or UVB) absorbing chemical that can beused in sunscreen composition.

In the context of the present invention the term “sol-gel microcapsule”relates to a core material which is coated by a sol-gel coating matrix.

In the context of the present invention the term “sunscreen activeingredient” refers to sol-gel microcapsules wherein the core material isa sunscreen compound.

SUMMARY OF THE INVENTION

The present invention relates to a sunscreen composition comprising asan active ingredient sol-gel derived microcapsules that encapsulateultraviolet (UV) absorbing compounds and any cosmetically acceptablevehicle. The encapsulation of the UV absorbers forms a barrier betweenthem and the human tissue, as well as between them and the otheringredients present in the formula and with the container in which theproduct is contained. The present invention further relates to sunscreencompositions in which cross reactivity between different sunscreencompounds, present in the same composition, is reduced or evenprevented.

The sunscreen active ingredient in the form of sol-gel microcapsules, isprepared by the method disclosed in U.S. patent application Ser. No.09/372,176. The size of the microcapsules obtained by this method can becontrolled to the range 0.01-100 μ, preferably 0.1-10 μ, by selectingsuitable reaction conditions. The hydrophobicity/hydrophilicitycharacter of the sol-gel microcapsules can be controlled by selectingsuitable sol-gel precursors and suitable reaction conditions and can bechosen to be compatible with the cosmetic vehicle to be used in thesunscreen composition; therefore, the microcapsules can be incorporatedeasily into any acceptable cosmetic vehicle. The sunscreen activeingredient can be incorporated into the cosmetic vehicle in the form ofan aqueous suspension of the sol-gel particles, or as a dried sol-gelpowder. In a preferred embodiment of this invention, the sol-gel derivedcapsule materials consist of the encapsulated matter and silica ororganically modified silica, in particular methyl modified silica.

The sunscreen compound can be selected from any acceptable UVA absorberor UVB absorber or combination thereof.

The compositions of the present invention can comprise a single activeingredient in the form of sol-gel microcapsules that encapsulate asingle sunscreen compound or several sunscreen compounds together, or acombination of the active ingredients, to obtain a composition with thedesired UV absorption spectrum. The concentration ratio of the activesunscreen ingredients present at the same composition is not limited andcan be of any value. The sunscreen compositions according to the presentinvention can comprise about 1 to about 8 wt. %, in particular fromabout 10 to about 50 wt % (weight percent of the final composition),water suspension of sol-gel derived capsules, in any cosmeticallyacceptable vehicle, or can comprise about 1 to about 40 wt. %, inparticular from about 5 to about 25 wt. % dry powder of sol-gelcapsules, in any cosmetically acceptable vehicle.

The present invention further relates to the sol-gel microcapsulesencapsulating sunscreen compound for use as a sunscreen activeingredient in sunscreen compositions. This sunscreen active ingredientcan be added to the cosmetic compositions at the end of the compositionprocess, without the application of heat or shear forces. However, suchsteps of composition formation may be carried out if required for thepurpose of formulating other constituents of the composition. Thesunscreen active ingredient can be incorporated in any cosmeticallyacceptable oil-in-water or water-in-oil compositions; the final productmay take the form of an oil, a gel, a solid stick, a lotion, a cream, amilk, an aerosol, a spray, a powder, a foam, a shampoo, a hairconditioner or lacquer or a make-up

The compositions according to the present invention are of a generalnature, and applicable to any sunscreen compounds currently used, aswell as to compounds that will be introduced in the future. It is alsoapplicable for other active ingredients that are regularly used incosmetic compositions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph of a supercoiled DNA remaining as a funciton ofirradiation time with respect to some samples.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to stable and safer sunscreen compositionsin which the contact between the sunscreen compounds and the humantissue, and the reactivity between sunscreen compound and othercomponents present in the composition are reduced or even prevented, byencapsulation of the sunscreen compound/s in a sol-gel derivedmicrocapsules. The selection of the cosmetic vehicle to be used in thecomposition is not limited and can be any cosmetically acceptablevehicle. The encapsulated sunscreen compound/s can be incorporated intothe cosmetic vehicle in the form of an aqueous suspension of the sol-gelparticles, or as a dried sol-gel powder.

The sol-gel microcapsules are prepared by the method disclosed in U.S.patent application Ser. No. 09/372,176, i.e., by a) emulsifyinghydrophobic solution comprising sol-gel precursors and at least oneultraviolet absorber in an aqueous solution under high shear forces andb) mixing and stirring the obtained emulsion with a second aqueoussolution at a suitably selected pH to obtain the sol-gel microcapsules.The size of the microcapsules so obtained can be controlled to the range0.01-100 μ, preferably 0.1-10 μ, by selecting suitable reactionconditions.

The sol-gel precursors can be selected from metal or semi-metal alkoxidemonomers, or metal ester monomers, or semi-metal ester monomers ormonomers of the formula M(R)_(n)(P)_(m), wherein M is a metallic or semimetallic element, R is a hydrolyzable substituent, n is an integer from2 to 6, P is a non polymerizable substituent and m is and integer from 0to 6, or partially hydrolyzed and partially condensed polymer thereof,or any mixture thereof.

In a preferred embodiment of this invention, the sol-gel microcapsulesare silica or organically modified silica microcapsules, producedthrough the sol-gel process disclosed in U.S. patent application Ser.No. 09/372,176. The term “organically modified silica microcapsules”refers to sol-gel microcapsules which are obtained when the sol-gelprecursors are of the formula M(R)_(n)(P)_(m), wherein M is Si, R is ahydrolyzable substituent, n is an integer from 2 to 5, P is a nonpolymerizable substituent and m is and integer from 1 to 6.

Since the encapsulation process is general, the capsules may containvarious sunscreen compounds or their mixtures.

The hydrophilicity/hydrophobicity character of the capsules isdetermined by the encapsulating material, and not by the sunscreencompound which is encapsulated inside it. Hence, lypophilic sunscreencompounds, which normally can be dissolved only in hydrophobic, fatcontaining phases, are easily incorporated in the aqueous phase of anycomposition, be it o/w (oil in water) or w/o (water in oil) emulsions,or in oil-free compositions, e.g. gels.

The compositions according to the present invention can comprise ahydrophilic composition as the cosmetic vehicle and water dispersiblemicrocapsules encapsulating sunscreen compounds that are hydrophobic,water-insoluble.

The invention further reveals that one or more sunscreen activeingredients are confined within particles of specific particle size,which is independent of the cosmetic vehicle, the compositionpreparation method, or the sunscreen concentration. This confinementprevents the rough feel and decreased coverage which are associated withundesired crystallization of sunscreen compounds, since in the event ofcrystallization the crystals are confined within the capsules,consequently the pleasant feel and efficient coverage are maintained.

The aqueous suspensions of encapsulated sunscreens compounds may contain1 to 50% wt. sunscreen compounds (a single sunscreen compound, or acombination of several sunscreens compounds together). In a preferredembodiment, the aqueous suspensions contain 20 to 40% wt. sunscreencompounds. The dried sol-gel silica powder may contain 1 to 85% wt.sunscreen compounds. In a preferred embodiment, the dried sol-gel silicapowders contain 50 to 80% wt. sunscreen compound.

The skilled formulator may use a suitable concentration of the aqueoussuspension or the powder, to obtain the desired concentration of eachsunscreen ingredient in the final composition. Thus, a cosmeticscreening composition is obtained, which comprises in a cosmeticallyacceptable vehicle, about 1 to about 80%, in particular from about 10 toabout 50% (w/w of the final composition) water suspension of the sol-gelderived capsules. In the same manner, a cosmetically acceptablescreening composition may be obtained, comprising about 1 to about 40%,in particular from about 5 to about 25% (w/w of the final composition)dry powder of sol-gel derived capsules.

The sol-gel containing suspension can easily be combined with o/wcompositions at the end of the composition, by simple mixing or stirringwith any suitable mixer or stirrer. No steps of heating or high shearforce mixing are required in order to achieve good mixing. Nonetheless,the encapsulating material, being inert and stable, can sustain highshear forces such as those active in a homogenizer (Ultra Torax forexample) and can sustain heating to 70° C. for the typical time used incomposition (up to 60 minutes), without any deterioration in theencapsulation or the capsules properties. Hence, if such processes arerequired for obtaining the desired formula, the aqueous suspension ofthe sol-gel derived sunscreen capsules can endure these processes.

If w/o composition is prepared, the aqueous suspension is easilyincorporated in the water phase by simple mixing or stirring. Thecombined water phases can then be handled as desired in a normalcomposition procedure known to the skilled formulator.

In all these cases, several aqueous suspensions of sol-gel derivedcapsules containing different sunscreen active ingredients may be addedtogether at any of these stages, in order to obtain formulae thatcontain several active ingredients in separate capsules, to reduce oreven to prevent their cross reactivity.

The sol-gel dried powder can also be easily combined with w/ocompositions at the end of the composition, by simple mixing or stirringwith any suitable mixer or stirrer. High shear forces may be applied tofacilitate fast and efficient mixing of the powder in the cosmeticvehicle. Also, the powder may be re-suspended in the aqueous phase priorto mixing the composition to ease efficient dispersion. The inert natureand stability of the sol-gel derived capsules allows the formulator toutilize these tools without damaging the encapsulation or the capsulesproperties.

The ease of composition when utilizing the sol-gel derived capsules is aunique advantage of this invention, and is an essential part of theinnovation disclosed herein.

Therefore, the composite encapsulated sunscreen active ingredient can beincorporated in cosmetically acceptable oil-in-water or water-in-oilcompositions; the final product may take the form of an oil, a gel, asolid stick, a lotion, a cream, a milk, an aerosol, a spray, a powder, afoam, a shampoo, a hair conditioner or lacquer or a make-up. Thecomposite encapsulated sunscreen active ingredient can be added to thecosmetic compositions at the end of the composition process, without theapplication of heat or shear forces. However, such steps of compositionmay be carried out if required for the purpose of formulating otherconstituents of the composition.

It is further demonstrated and emphasized in the case of sunscreenactive ingredients, which arc solid in nature, or tend to form crystalsif the composition is not carefully balanced. Some examples of suchactive ingredient include benzophenones, dibenzoylmethanes, camphor andphenyl benzimidazole sulfonic acid in the presence of α and β hydroxyacids. The encapsulation process confines these active ingredients, evenin the event of crystallization, within the capsules. Consequently, theproblems normally associated with crystals formation, i. e. rough feeland poor coverage, are prevented.

The particle size of the capsules is determined in the encapsulationprocess, consequently it does not change as a result of the formula orthe material encapsulated inside it, even in the event of crystalformation.

An important feature of the capsules is their very efficientencapsulation of the lypophilic sunscreen compounds, which reduces oreven prevents their leaching out into aqueous phases and into a largenumber of cosmetically acceptable oils. Thus, incorporation ofincompatible active ingredients when each of them is encapsulatedseparately in the sol-gel capsules is a very efficient method to reduceor even to prevent their cross reactivity.

Another important objective of this invention is to provide safersunscreen products. As discussed in the background of this invention,several research groups around the world have demonstrated thepotentially harmful effects of several sunscreen products on several invitro models. It is also recognized that with the increased use ofsunscreen product in the world, a growing number of incidents ofphotoallergy are being reported. In fact, some sunscreen products thatare allowed for use by the regulations have been practically withdrawnfrom the market due to the high number of reported phoroallergyincidents related to them (Schauder and H. Ippen, European UVSunfilters, Conference Proceedings, Paris November 17-18 1998, p. 14).With the encapsulated products, the contact between the active sunscreenmolecules or its photodegradation products with the human tissue iseliminated. Consequently the harmful potential of the sunscreen activeingredients is dramatically minimized.

It is a further object of this invention to provide a screeningcomposition which reduces or even prevents the penetration by diffusionof sunscreen active ingredient into plastic containers, which may resultin fracturing of the packaging material, unacceptable colouring of whitepackaging material with time, and assay problems.

It has also been found that utilizing the encapsulated sol-gelsunscreen, active ingredients that form crystals in regular compositionscan be easily used, as even in the event of crystallization the crystalsare confined within the capsule, hence pleasant feel and efficientcoverage are maintained.

The sunscreen compound can be selected from the group consisting of2-ethylhexyl 4-methoxyciinamate, 4-aminobenzoic acid,2-ethylhexyl-N,N-dimethyl-4-aminobenzoate, 2-cyano-3,3-diphenylacrylicacid 2-ethylhexyl ester (Octocrylene), 2-hydroxy-4-methoxy-benzophenone(Oxybenzone) 2-phenylbenzimidizole-5-sulfonic acid,3,3,5-trimethyl-cyclohexyl-salicilate (Homosalate) octyl salycilate,4,4′-methoxy-t-butyldibenzoylmethane, 4-isopropyl dibenzoylmethane,3-(4-methylbenzyledene) camphor, 3-benzylidene camphor, triethanolaminesalicylate, 4-N,N-(2-ethylhexyl)methyl aminobenzoic acid ester of2,4-dihydroxybenzophenone, 4-N,N-(2-ethylhexyl)methyl aminobenzoic acidester of 4-hydroxyd ibenzoylmethane, 4-N,N-(2-ethylhexyl)methylaminobenzoic acid ester of 2-hydroxy-4-(2-hydroxyethoxy)benzophenone,4-N,N-(2-ethylhexyl)methyl aminobenzoic acid ester of4-(2-hydroxyethoxy)dibenzoylmethane, sodium 3,4-dimethoxyphenylglyoxylate, benzophenone-4, diethanolaminemethoxycinnamate, Bisymi-dazylate(2,2-(1,4-Phenylene)bis)-1H-benzimidazole-4,6-disulfonic acid,monosodium salt)), camphor benziakonium methosulfate, terephthalidenedicamphor sulfonic acid, benzylidene camphor sulfonic acid,octyltriazone, methylene bis-benzotriazolyl tetramethylbutyl phenol,Aniso-triazinc(2,4-bis-{[4-(2-Ethyl-hexyloxy)-2-hydroxy]-phenyl}-6-(4-methoxy-phenyl)-(1,3,5)-triazine),Dioctyl butamido triazone, 3-benzylidene camphor, Drometrizoletrisiloxane, Dimethico-diethyl-benzal-malonate, polyacrylamidomethylbenzylidene camphor, and mixtures thereof.

The sunscreen compound can also include one or more of the following:ethylhexyl-a-cyano-b-phenyl cinnamate, triethanolamine salicylate, amylsalicylate, p-isopropyl phenyl salicylate, and 4-isopropyl benzylsalicylate.

The sunscreen active ingredient can be in the form of a dried sol-gelpowder.

The cosmetic vehicle according to the present invention can be selectedfrom the group consisting of fatty alcohols, fatty acids, fatty acidsesters, fatty acid triglycerides, lanolin, natural or synthetic oils andwaxes, water in oil and oil in water emulsions.

The sunscreen composition can further comprise cosmetic adjuvantsselected from thickeners, emollients, emulsifiers, humectants,surfactants, film forming agents, preservatives, antifoaming agents,fragrances, lower monoalcoholic polyols, propellants, colorants andpigments.

The sunscreen composition according to the present invention can furthercontain additives selected from the group consisting of sunscreenactives, sunless tanning actives, skin lightening actives anti-acneactives, anti-skin wrinkling actives, vitamins, nonsteroidalanti-inflammatory actives, anesthetic actives, anti-pruritic actives,anti-microbial actives, and mixtures thereof wherein said additives areeither dissolved in the cosmetic vehicle or are also in the form ofsol-gel microcapsules.

The sunscreen composition according to the present invention can furthercomprise physical sunblock active ingredients selected from the groupconsisting of titanium dioxide, zinc oxide, iron oxide, and mixturesthereof wherein said physical sunblock ingredients can be of anycommercially available grade, including surface treated particles suchas titanium dioxide, which has been surface treated with silica,alumina, stearic acid or mixtures thereof, or any other surfacetreatment.

The sunscreen composition according to the present invention can furthercomprise α or β-hydroxy acids such as salycilic acid, glycolic acid,lactic acid, retinoic acid and mixtures thereof.

The present invention further relates to sol-gel microcapsulesencapsulating at least one sunscreen compound for use as a sunscreenactive ingredient in sunscreen products by easy incorporation into anycosmetically acceptable vehicle without the use of any shear forces.

The sunscreen composition according to the present invention can furthercomprise one or more ultraviolet absorbing compounds, not enclosedwithin sol-gel microcapsules, that are water soluble.

The sunscreen composition according to the present invention can alsocomprise water soluble ultraviolet absorbing compounds that are2-Phenylbenzimidazole-5-sulfonic acid, sodium 3,4-dimethoxyphenylglyoxylate, benzophenone-4, diethanolaminemehtoxycinnamate, Bisymi-dazylate(2,2′-(1,4-Phenylene)bis)-1H-benzimidazole-4,6-disulfonic acid,monosodium salt)), camphor benzalkonium methosulfate, terephthalidenedicamphor sulfonic acid, or benzylidene camphor sulfonic acid.

The sunscreen composition according to the present invention can furtherbe formulated such that it is oil-free.

The sunscreen composition according to the present invention can alsocomprise one or more ultraviolet absorbing compounds, which are notenclosed within sol-gel microcapsules, that are water insolublemicronized solids.

The sunscreen composition according to the present invention can furthercomprise water insoluble micronized solid ultraviolet absorbingcompounds that are octyltriazone, methylene bis-benzotriazolyltetramethylbutyl phenol, Aniso-triazine(2,4-bis-{[4-(2-Ethyl-hexyloxy)-2-hydroxy]-phenyl}-6-(4-methoxy-phenyl)-(1,3,5)-triazine),Dioxtyl butamido triazone, oxybenzone (benzophenone-3), benzophenone-1,benzophenone-2, benzophenone-6, benzophenone-8,4,4′-methoxy-t-butyldibenzoylmethane, 4-isopropyl dibenzoylmethane,4-methylbenzylidene camphor, 3-benzylidene camphor, Polyacrylamidomethylbenzylidene camphor, Drometrizole trisiloxane, orDimethico-diethyl-benzal-malonate.

Following are preferred embodiments for said sol-gel microcapsules:

(One) Sol-gel microcapsules encapsulating 2-ethylhexyl4-methoxycinnamate, as well as other cinnamate derivatives such asisopentyl 4-methoxycinnamate, diethanolamine methoxycinnamate,2-ethoxyethyl-4-methoxycinnamate and mixtures thereof.

(Two) Sol-gel microcapsules encapsulating Oxybenzone (benzophenone-3),as well as other benzophenone derivatives such as benzophenone-4,benzophenone-8, benzophenone-1, benzophenone-2, benzophenone-5,benzophenone-9 and mixtures thereof.

(Three) Sol-gel microcapsules co-encapsulating 2-ethylhexyl4-methoxycinnamate and oxybnezone, as well as as other cinnamatederivatives such as in preferred embodiment (a) and other benzophenonederivatives such as in preferred embodiment (b) and mixtures thereof.

(Four) Sol-gel microcapsules co-encapsulating Homosalate and4,4′-methoxy-t-butyldibenzoylmethane, as well as other derivatives ofsalicylate such as octyl salycilate, 4-isopropylbenzyl salicylate anddibenzoylmethanes such as isopropyl dibenzoyl methane and mixturesthereof.

(Five) Sol-gel microcapsules co-encapsulating Homosalate and4,4′-methoxy-t-butyldibenzoylmethane and a suitable cosmetic oil such asCapric/caprylic triglyceride, octyl palmitate, C12-C15 alkyl benzoate,dioctyl maleate, propylene glycol dicaprylate/dicaprate, diisopropyladipate, hexyl laurate, and mixtures thereof, as well as otherderivatives of salicylate and dibenzoylmethanes and mixtures thereof.

(Six) Sol-gel microcapsules co-encapsulating 2-cyano-3,3-diphenylacrylicacid 2-ethylhexyl ester (Octocrylene), and4,4′-methoxy-t-butyldibenzoylmethane, as well as other derivatives ofdibenzoylmethane such as isopropyldibenzoylmethane and mixtures thereof.

(Seven) Sol-gel microcapsules co-encapsulating2-cyano-3,3-diphenylacrylic acid 2-ethylhexyl ester (Octocrylene) and4,4′-methoxy-t-butyldibenzoylmethane and a suitable cosmetic oil such asCapric/caprylic triglyceride, octyl palmitate, C12-C15 alkyl benzoate,dioctyl maleate, propylene glycol dicaprylate/dicaprate, diisopropylsadipate, hexyl laurate, and mixtures thereof, as well as otherderivatives of dibenzoylmethane such as isopropyl dibenzoylmethane andmixtures thereof.

(Eight) Sol-gel microcapsules co-encapsulating Homosalate and3-(4-methylbenzyledene) camphor, as well as other derivatives ofsalicylate such as octyl salicylate, 4-isopropylbenzyl salicylate andother camphor derivatives such as 3-benzylidene camphor and mixturesthereof.

(Nine) Sol-gel microcapsules co-encapsulating Homosalate and3-(4-methylbenzyledene) camphor and a suitable cosmetic oil such asCapric/caprylic triglyceride, octyl palmitate, C12-C15 alkyl benzoate,Dioctyl maleate, propylene glycol dicaprylate/dicaprate, diisopropyladipate, hexyl laurate, and mixtures thereof, as well as otherderivatives of salicylate such as octyl salicylate, 4-isopropylbenzylsalicylate and other camphor derivatives such as 3-benzylidene camphorand mixtures thereof.

(Ten) Sol-gel microcapsules encapsulating 2-ethylhexylN,N-dimethyl-p-aminobenzoate, as well as other aminobenzoic acidderivatives such as 4-aminobenzoic acid (PABA), glyceril amionobenzoate,menthyl anthranilate, ethyl PABA, amyl dimethyl PABA and mixturesthereof.

The sunscreen composition according to the present invention cancomprise any of the preferred embodiment (one) to (ten) or a combinationthereof in any acceptable cosmetic vehicle. Following are preferredembodiments of sunscreen compositions according to the presentinvention:

(Eleven) A sunscreen composition comprising of preferred embodiments(one) and (four) in any acceptable cosmetic vehicle

(Twelve) A sunscreen composition comprising of preferred embodiments(one) and (five) in any acceptable cosmetic vehicle

(Thirteen) A sunscreen composition comprising of preferred embodiments(one) and sol-gel microcapsules encapsulating cinoxate in any acceptablecosmetic vehicle.

The compositions revealed by this invention are of general nature, andthe method according to which they are prepared is applicable to anysunscreen compounds currently used, as well as to sunscreen compoundsthat will be introduced in the future. It is also applicable for othercompounds that are regularly used in cosmetic compositions. Furthermore,because of the easy incorporation of the sunscreen active ingredientsand the ability to control their hydrophilicity/hydrophobicity characterand the capsules size, the cosmetic vehicle to be used with thesunscreen active ingredients is not limited to any group and can be anycosmetically acceptable vehicle.

EXAMPLES

The following examples clarify and demonstrate the invention and are notunder any circumstances exclusive. All percentage data is given inweight percentage (w/w) unless specified otherwise.

Example 1 Co-encapsulation Homosalate (HMS) and ButylMethoxydibenzoylmethane (BMDBM)

12.85 g BMDBM was dissolved in 38 g HMS. The obtained mixture wasdissolved in 51.4 tetraethoxysilane (TEOS) and the organic phase wasemulsified in 240 g of aqueous solution containing 1% cetyltrimethylammonium chloride (CTAC) under high shear forces using an Ultra-TurraxT-25 basic with S 25 KR-18G dispersing tool (IKA) at 19,000 rpm. Thevessel walls were cooled by immersion in an ice-water bath during thehomogenizing process. The such obtained emulsion was then poured into anIKA LR-A 1000 Laboratory reactor, equipped with Eurostar Powercontrol-visc P4 stirrer, containing 350 NaOH aqueous solution at pH11.3. The emulsion was stirred at room temperature for 24 hours. Theproduct was precipitated in a centrifuge at 20,000 g, rinsed byre-suspension in deionized water, precipitated again and finallyre-suspended in a 1% polyvinyl pyrrolidon (PVP K30, ISP) to afford astable dispersion containing 31.3% HMS and 10% BMDBM in the suspension.

The obtained suspension is smooth, pleasant to touch and can beincorporated into various cosmetic vehicles to obtain a sunscreencomposition useful for protecting against ultraviolet radiation.

Example 2 Encapsulation of 2-Ethylhexyl p-Methoxycinnamate (OMC) inSilica

33 g OMC was dissolved in 33 g TEOS and the organic phase was treated asdescribed in example 1.

The isolated product consisted of an aqueous suspension of silicacapsules, containing 35.8% OMC (w/w in final suspension).

The obtained aqueous suspension is smooth, pleasant to touch and can beincorporated into various cosmetic vehicles to obtain a sunscreencomposition useful for protecting against ultraviolet radiation.

Example 3 Co-encapsulation of Octocrylene and BMDBM in Silica

4.1 g BMDBM was dissolved in 12.4 g octocrylene. The obtained mixturewas dissolved in 49.5 g TEOS and the organic phase treated as describedin example 1.

The isolated product consisted of an aqueous suspension of silicacapsules, containing 23.5% octocrylene and 7.2% BMDBM (w/w in finalsuspension).

The obtained aqueous suspension is smooth, pleasant to touch and can beincorporated into various cosmetic vehicles to obtain a sunscreencomposition useful for protecting against ultraviolet radiation

Example 4 Encapsulation of 2-Ethylhexyl N,N-Dimethyl-p-aminobenzoate(Pad-O) in Silica

16.5 g Pad-O was dissolved in 49.5 g TEOS. The obtained mixture wastreated as described in example 1. The isolated product consisted of anaqueous suspension of silica capsules, containing 28.5% Pad-O (w/w infinal suspension).

The obtained aqueous suspension is smooth, pleasant to touch and can beincorporated into various cosmetic vehicles to obtain a sunscreencomposition useful for protecting against ultraviolet radiation

Example 5 Encapsulation OMC in Methyl Modified Silica

2.75 g OMC was dissolved in 8.25 g methyltriethoxysilane. The organicphase was emulsified in 50 g of aqueous solution containing 1%ethoxylated sorbitan monooleate (Tween-80, ICI). under high shear forces(as described in example 1). The such obtained emulsion was then pouredinto 50 g stirred ammonia solution (pH 11.2). The emulsion is stirred atroom temperature for 24 hours, followed by stirring at 50° C. for 3hours. The obtained powder is washed with water and freeze dried to givea fine silica powder containing 24% OMC.

The obtained powder is smooth, pleasant to touch and can be incorporatedinto various cosmetic vehicles to obtain a sunscreen composition usefulfor protecting against ultraviolet radiation.

Examples 6 Oil in Water Composition Containing Hydrophilic Suspension ofEncapsulated Sunscreen in Silica

INCI name % w/w PHASE A 1 Squalane 5.00 2 Cetyl alcohol 2.50 3 Glycerylstearate & PEG-100 stearate 5.00 4 Propylparabene 0.10 PHASE B 5 Aqua(water) 50.20 6 Methylparabene 0.20 7 Disodium EDTA 0.05 8Imidazolidinyl urea 0.50 PHASE C 9 Methylchloroisothiazolinone & 0.05Methylchlorothiazolinone & Benzyl alcohol PHASE D 10  Silica/OMC/BMDBM36.40 (20.6% OMC, 3.8% BMDBM in water suspension)

Phase A was heated to 75° C. and mixed. Phase B was heated to 75° C. andmixed. Phase B was poured into phase A and stirred for 5 minutes,followed by 25 minutes homogenization. The mixture was cooled to 55° C.,and phase C was added while stirring. The mixture was cooled further to40° C. and phase D was added while stirring. The cream was stirred foranother 5 minutes.

The obtained composition has an estimated SPF of ˜10 (preliminary teston 3 volunteers) and is stable, uniform and pleasant to touch.

Examples 7 Oil in Water Composition Containing Hydrophilic Suspension ofEncapsulated Sunscreen in Silica.

INCI name % w/w PHASE A 1 Paraffinium liquiduim (minral oil) 5.00 2Decyl oleate 5.00 3 Dimethicone 1.00 4 Cetearyl alcohol 1.00 5 Glycerylstearate 3.00 6 Potassium cetyl phosphate 2.00 PHASE B 7 Aqua (water)47.25 8 Xanthan gum 0.15 9 Propylene glycol 5.00 10 2-Bromo-2-nitropropane-1,3 diol & 0.50 Methylparabne & Phenoxyethanol &Propylbarabne PHASE C 11  Lactic acid 88% (in water) 0.10 PHASE D 11 Silica/OMC 30.00 (25% OMC in water suspension)

Phase A was heated to 65° C. and mixed. Phase B was heated to 65° C. andmixed. Phase B was cooled, and phase C was added to obtain pH 4.5-4.8.Phase D was stirred into phase B. The combined phase was heated again to65° C. and phase A was stirred in. The combined mixture was homogenizedbriefly with a high shear mixer, and the composition was stirred untilcooled to room temperature.

The obtained composition is stable, uniform and pleasant to touch. Thein vitro SPF value measured for this composition is 10.4.

Examples 8 Water in Oil Composition Containing Hydrophilic Suspension ofEncapsulated Sunscreen in Silica

INCI name % w/w PHASE A 1 Caprylic/Capric triglyceride 9.00 2 C12-C15Alkyl benzoate 7.50 3 Diisostearoyl polyglyceryl-3 diisostearate 3.00 4Hydrogenated castor oil 0.30 5 Cera Alba (Beeswax) 0.20 PHASE B 6 Aqua(water) 47.25 7 Magnesium sulfate 1.00 8 Glycerin 1.00 92-Bromo-2-nitropropane-1,3 diol & 0.50 Methylparabne & Phenoxyethanol &Propylbarabne PHASE C 11  Lactic acid 88% (in water) 0.10 PHASE D 12 Silica/OMC 30.00 (25% OMC in water suspension)

Phase A was heated to 70° C. and stirred. Phase B was heated to 70° C.and stirred. Phase B was cooled, and phase C was added to obtain pHbelow 5.0. Phase D was stirred into phase B. The combined phase washeated again to 70° C. and phase A was stirred in. The mixture wascooled with stirring, and homogenized at 30° C.

The composition is stable, uniform and pleasant to touch. The in vitroSPF value measured for this composition is 12.8.

Examples 9 Water in Oil Composition Containing Hydrophobic Powder ofEncapsulated OMC in Methyl Modified Silica

INCI name % w/w PHASE A 1 Caprylic/Capric triglyceride 9.00 2 C12-C15Alkyl benzoate 7.50 3 Diisostearoyl polyglyceryl-3 diisostearate 3.00 4Hydrogenated castor oil 0.30 5 Cera Alba (Beeswax) 0.20 PHASE B 6 Aqua(water) 65.0 7 Magnesium sulfate 1.00 8 Glycerin 1.00 92-Bromo-2-nitropropane-1,3 diol & 0.50 Methylparabne & Phenoxyethanol &Propylbarabne PHASE C 1 Silica/OMC 12.5 (60% OMC in the dry powder)

Phase A was heated to 70° C. and stirred. Phase B was heated to 70° C.and stirred. Phase C was added to phase A with stirring. All phases werecombined together, cooled with stirring and homogenized. Example 10

Phototoxicity Tests of Encapsulated Sunscreen Compounds Versus FreeSunscreen Compounds.

The phototoxicity tests are based on the survival of a yeast strain,XD83. A single colony of yeast is inoculated into growth medium, andharvested during the exponential growth. The cells are suspended at aknown concentration in a phosphate buffer, to afford a uniformpopulation of cells. The cells are illuminated with simulated sunlight(13 mW/cm²) in the absence or presence of test compounds with continousstirring. Samples are taken at increasing times (0, 10, 20, 30 minutesof illumination). The samples are analyzed semi-quantitatively, byapplying two dilutions of the sample as small droplets (10 μl) to thesurface of nutrient agar plates, and incubated at 37° C. for 48 hours.Patches of growth are found around the droplet. It can be easily seenwhen growth has been decreased. Sunscreen samples are introduces as 1000μM concentration of the major UVB sunscreen active ingredient.Padimate-O and BMDBM are used as positive controls, both showing astrong phototoxic effect on the growth of the yeast cell. The resultsare summarized in table 1.

TABLE 1 Phototoxicity test results. Sample Content PhototoxicityPadimate-O (Positive blank) Clearly toxic BMDBM (Positive blank) Moretoxic than Padimate-O Light alone (Blank) Non-toxic 132 (I) Encapsulated(OMC + BMDBM)^(a) Non-toxic 139 Free (OMC + BMDBM)^(a) Toxic about equalto Padimate-O 135 Blank cream Slightly toxic ^(a)7.5% OMC, 1.4 BMDBM.

The results show that encapsulation of the sunscreen active ingredientscreates a barrier between the entrapped sunscreen and itsphotodegradation products and the yeast cells. Consequently,phototxicity is prevented.

Example 11 Plasmid DNA Nicking Tests of Encapsulated Sunscreen CompoundsVersus Free Sunscreen Compounds

DNA plasmid nicking assay is outlined in Dunford et al, FEBS letts 418,87-90. The light source consist of a 250-watt ozone free xenon lamp(Spiers Robertson) with a reflector, condensing lens, dichroic mirror todissipate infra-red irradiation and a 2-mm Schott WG 320 filter. Thetotal irradiace between 290 and 400 nm is about 5 MW/cm².

2.5 μg of supercoiled plasmid DNA in 50 μl of 0.01 M sodium phosphatebuffer, pH 7.5, was irradiated in an upturned Eppendorf lid on a brassblock embedded in ice and 10 μl samples were taken at each time pointand kept on ice. They were analyzed by electrophoresis on neutral 1%agarose gels (1% w/v agarose, 0.5 TBE, 0.3 μg ethidium bromide/ml) runin 0.5 TBE buffer in a GNA 100 or GNA 200 gel tanks (Pharmacia), at 15V/cm for minigels and 5 v/cm for regular gels, which were stained withethidium bromide, viewed on a 313 nm UV transilluminator andphotographed on a Polaroid 665 positive/negative instant pack film. Thenumber of lesions per molecule of DNA was calculated by measuring theintensity of the supercoiled DNA by densitometry of the agarose gelnegative using a model GS-670 imaging densitometer (Bio-Rad). When thetotal amount of damage inflicted on the DNA is small the amount ofundamaged DNA left after an illumination gives a direct measure of thenumber of strand breaks inflicted. As positive controls Padimate-O andBMDBM are used (at saturation concentrations). It has been shown thatboth these compounds inflict strand breaks on DNA when they areilluminated in vitro.

The samples, which are o/w emulsions, were added to DNA as suspensionsin buffer, so as to arrive as a notional concentration of 1000 μM withrespect to the UVB absorbing component. As most sunscreen chemicals arevirtually insoluble in water this ensures that they are present atsaturation.

FIG. 1 shows that sample 139, in which OMC and BMDBM are present free inthe cosmetic composition, significant damage is inflicted on the DNA,similar to the damage inflicted by the BMDBM used as the positivecontrol. Sample 132, in which OMC and BMDBM are encapsulated, does notinflict damage on the DNA, and is similar to plasmid alone, withoutadded chemicals.

It is therefore concluded that encapsulation of sunscreen activeingredients creates a barrier not only for the sunscreens but also totheir photodegradation products. This encapsulation reduces and evenprevents the adverse reactions found in the free systems, which inflictdamage on the DNA.

Example 12 Water in Oil Composition Containing Hydrophilic Suspension ofEncapsulated Sunscreen in Silica and Water Soluble Sunscreen

INCI Name % w/w PHASE A 1 Cetyl dimethicone copolyol 2.00 2Isohexadecane 10.00 3 Cetearyl isononate 8.00 4 Octyl stearate 8.00PHASE B 5 Sodium chloride 1.00 6 Glycerin 4.00 7 Aqua 34.00 PHASE C 8OMC/Silica (35% OMC in water 25.00 suspension) 92-Phenylbenzimidazole-5-sulfonic 8.00 Acid

Phase C was neutralised with NaOH (10 wt% solution) and added to phaseB. Phase BC was added slowly with stirring to phase A. The mixture washomogenized for 1 minute.

The obtained composition is stable, uniform and pleasant to touch. TheSPF obtained in vivo on 6 volunteers was 23.7±5.2.

Example 13 Water in Oil Composition Containing Hydrophilic Suspsensionof Encapsulated Sunscreen in Silica and TiO²

INCI Name % w/w PHASE A 1 Ceryl dimethicone Copolyol 2.00 2Isohexadecane 6.25 3 Cetearyl isononate 5.50 4 Octyl stearate 5.50 5C12-C15 Alkyl benzoate, Titanium 8.75 Dioxide, Triethyl citrate,Alumina, Dimethicone, Polyglycerin-3-Diisostearate PHASE B 6 Sodiumchloride 1.00 7 Glycerin 4.00 8 OMC/Silica (35% OMC in water 25.00suspension) 9 Aqua 42.00

Phase B was added slowly to phase A with stirring. The mixture washomogenized for 1 minute.

The obtained composition is stable, uniform and pleasant to touch. TheSPF obtained in vivo on 6 volunteers was 22.9±5.4.

Example 14 Extraction of OMC from the Capsules after Application of theSunscreen Composition

A sample of the sunscreen composition of example 13 (10÷35 mg) wasapplied evenly to a microscope cover glass (18×18 mm). The slide wasdried in a ventilated oven (46° C.) for 3 hours. The dried specimen wasthen put into a vial containing 7±0.5 g Caprylic/capric triglyceride.The vial was shaken for 1 hour at r.t., and a sample of the oil wasfiltered (0.2 micron cut off), diluted with isopropanol and the quantityof OMC was measured spectrometrically. Only 9.2±1.5% of the total amountof OMC in the sample was found free in the oil, meaning that >90% of theencapsulated OMC is still retained in the capsules.

In comparison, a similar extraction experiment was conducted using asunscreen composition as in Example 13, but replacing the encapsulatedOMC with the free UV absorber. It was found that all the amount of OMCwas extracted to the oil.

What is claimed is:
 1. A safe and stable sunscreen composition,comprising at least one sunscreen active ingredient and a cosmeticallyacceptable vehicle, wherein said sunscreen active ingredient is in theform of sol-gel microcapsules containing at least one sunscreencompound; and the at least one sunscreen compound is selected from thegroup consisting of sodium 3, 4-dimethoxyphenylglyoxylate,benzophenone-4, diethanolamine methoxycinnamate, Bisymi-dazylate(2,2-(1,4-Phenylene)bis)-1H-benzimidazole-4,6-disulfonic acid,monosodium salt)), camphor benzlakonium methosulfate, terephthalidenedicamphor sulfonic acid, benzylidene camphor sulfonic acid,octyltriazone, methylene bis-benzotriazolyl tetramethylbutyl phenol,Aniso-triazine(2,4-bis-{-phenyl}-6-(4-methoxy-phenyl)-(1,3,5)-triazine), Dioctylbutamido triazone, 3-benzylidene camphor, Drometrizole trisiloxane,Dimethico-diethyl-benzal-malonate, polyacrylamidomethyl benzylidenecamphor, and mixtures thereof.
 2. Sol-gel microcapsules encapsulating atleast one sunscreen compound for use as a sunscreen active ingredient,wherein said at least one encapsulated sunscreen compound comprises atleast one of isopentyl 4-methoxycinnamate, diethanolaminemethoxycinnamate, 2-ethoxyethyl-p-methoxycinnamate,ethylhexyl-a-cyano-b-phenyl cinnamate, and mixtures thereof.
 3. Sol-gelmicrocapsules encapsulating at least one sunscreen compound for use as asunscreen active ingredient, wherein said sol-gel microcapsulesco-encapsulating a sunscreen compound selected from the group consistingof 2-ethylhexyl 4-methoxycinnamate, isopentyl 4-methoxycinnamate,diethanolamine methoxycinnamate, 2-ethoxyethyl-p-methoxycinnamate,ethylhexyl-a-cyano-b-phenyl cinnamate and mixtures thereof together witha compound selected from the group consisting of Oxybenzone(benzophenone-3), benzophenone-4, benzophenone-8, benzophenone-1,benzophenone-2, benzophenone-5, benzophenone-9 and mixtures thereof. 4.Sol-gel microcapsules encapsulating at least one sunscreen compound foruse as a sunscreen active ingredient, wherein said sol-gel microcapsulesco-encapsulating a derivative of salicylate selected from the groupconsisting of Homosalate, octyl salycilate, 4-isopropylbenzylsalicylate, thiethanolamine salicylate, amyl salicylate, p-isopropylphenyl salicylate, 4-isopropyl benzyl salicylate, and mixtures thereoftogether with a derivative of dibenzoylmethane selected from the groupconsisting of isopropyl dibenzoylmethane,4,4′-methoxy-t-butyldibenzoylmethane and mixtures thereof.
 5. Sol-gelmicrocapsules encapsulating at least one sunscreen compound for use as asunscreen active ingredient, wherein said sol-gel microcapsulesco-encapsulating a derivative of salicylate selected from the groupconsisting of Homosalate, octyl salycilate, 4-isopropylbenzylsalicylate, thiethanolamine salicylate, amyl salicylate, p-isopropylphenyl salicylate, 4-isopropyl benzyl salicylate, and mixtures thereoftogether with a derivative of dibenzoylmethane selected from the groupconsisting of isopropyl dibenzoylmethane,4,4′-methoxy-t-butyldibenzoylmethane and mixtures thereof and with asuitable cosmetic oil.
 6. Sol-gel microcapsules according to claim 5,wherein the cosmetic oil is selected from the group consisting ofCapric/caprylic triglyceride, octyl palmitate, C12-C15 alkyl benzoate,dioctyl maleate, propylene glycol dicaprylate/dicaprate, diisopropylsadipate, hexyl laurate, and mixtures thereof.
 7. Sol-gel microcapsulesencapsulating at least one sunscreen compound for use as a sunscreenactive ingredient, wherein said sol-gel microcapsules co-encapsulating aderivative of salicylate selected from the group consisting ofHomosalate, benzyl salicylate, octyl salicylate, triethanolaminesalicylate, potassium salicylate, amyl salicylate, p-isopropyl phenylsalicylate, 4-isopropyl benzyl salicylate and mixtures thereof, togetherwith a camphor derivative selected from the group consisting of3-(4′-methylbenzylidene) camphor, 3-benzylidene camphor,3-(4-methoxybenzylidene) camphor, and mixtures thereof.
 8. Sol-gelmicrocapsules according to claim 7, further co-encapsulating a suitablecosmetic oil.
 9. Sol-gel microcapsules encapsulating at least onesunscreen compound for use as a sunscreen active ingredient, whereinsaid sol-gel microcapsules encapsulating an aminobenzoic acid derivativeselected from the group consisting of glyceril aminobenzoate, ethylPABA, amyl dimethyl PABA, methyl anthranilate and mixtures thereof. 10.A safe and stable sunscreen composition comprising at least onesunscreen active ingredient and a cosmetically acceptable vehicle,wherein said sunscreen active ingredient is in the form of sol-gelmicrocapsules containing at least one sunscreen compound; thecosmetically acceptable vehicle contains at least one ultravioletabsorbing compound not enclosed within sol-gel microcapsules; and saidat least one ultraviolet absorbing compound is water soluble.
 11. Asunscreen composition according to claim 10, wherein the water solubleultraviolet absorbing compounds are selected from the group consistingof 2-Phenylbenzimidazole-5-sulfonic acid, sodium 3,4-dimethoxyphenylglyoxylate, benzophenone-4, diethanolaminemehtoxycinnamate, Bisymi-dazylate(2,2′-(1,4-Phenylene)bis)-1H-benzimidazole-4,6-disulfonic acid,monosodium salt)), camphor benzalkonium methosulfate, terephthalidenedicamphor sulfonic acid, and benzylidene camphor sulfonic acid.
 12. Asunscreen composition according to claim 10, which is oil-free.
 13. Asafe and stable sunscreen composition comprising at least one sunscreenactive ingredient and a cosmetically acceptable vehicle, wherein saidsunscreen active ingredient is in the form of sol-gel microcapsulescontaining at least one sunscreen compound; the cosmetically acceptablevehicle contains at least one ultraviolet absorbing compound notenclosed within sol-gel microcapsules; and said at least one ultravioletabsorbing compound is a water insoluble micronized solid.
 14. Asunscreen composition according to claim 13, wherein the water insolublemicronized solid ultraviolet absorbing compounds are selected from thegroup consisting of octyltriazone, methylene bis-benzotriazolyltetramethylbutyl phenol, Aniso-triazine(2,4-bis-{[4-(2-Ethyl-hexyloxy)-2-hydroxy]-phenyl}-6-(4-methoxy-phenyl)-(1,3,5)-triazine),Dioxtyl butamido triazone, oxybenzone (benzophenone-3), benzophenone-1,benzophenone-2, benzophenone-6, benzophenone-8,4,4′-methoxy-t-butyldibenzoylmethane, 4-isopropyl dibenzoylmethane,4-methylbenzylidene camphor, 3-benzylidene camphor, Polyacrylamidomethylbenzylidene camphor, Drometrizole trisiloxane, andDimethico-diethyl-benzal-malonate.
 15. A sunscreen composition accordingto claim 13, which is oil-free.
 16. Sol-gel microcapsules according toclaim 2, wherein said at least one encapsulated sunscreen compoundfurther comprises 2-ethylhexyl 4-methoxycinnamate.
 17. Sol-gelmicrocapsules according to claim 9, further encapsulating at least oneof 2-ethylhexyl N,N′ dimethyl-4-aminobenzoate, and 4-aminobenzoic acid(PABA).
 18. The sunscreen composition according to claim 1, wherein theat least one sunscreen compound further comprises at least one of2-ethylhexyl 4-methoxycinnamate, 4-aminobenzoic acid, 2-ethylhexylN,N-dimethyl-p-aminobenzoate, 2-cyano-3,3-diphenylacrylic acid2-ethylhexyl ester (Octocrylene), 2-hydroxy-4-methoxy-benzophenone(Onzone), 2-phenylbenzimidizole-5-sulfonic acid,3,3,5-trimethyl-cyclohexyl-salicylate (Homosalate), octyl salycilate,4,4′-methoxy-t-butyldibenzoylmethane, 4-isopropyl dibenzoylmethane,3-(4′-methylbenzyledene) camphor, 3-benzylidene camphor, triethanolaminesalicylate, 4-N,N-(2-ethylhexyl)methyl aminobenzoic acid ester of2,4-dihydroxybenzophenone, 4-N,N-(2-ethylhexyl)methyl aminobenzoic acidester of 4-hydroxydibenzoylmethane, 4-N,N-(2-ethylhexyl)methylaminobenzoic acid ester of 2-hydroxy-4-(2-hydroxyethoxy)benzophenone,4-N,N-(2-ethylhexyl)methyl aminobenzoic acid ester of4-(2-hydroxyethoxy)dibenzoylmethane.